From: Andrew Patterson <andrew.patterson@hp.com>
To: Luben Tuikov <luben_tuikov@adaptec.com>
Cc: "Salyzyn, Mark" <mark_salyzyn@adaptec.com>,
dougg@torque.net, Linus Torvalds <torvalds@osdl.org>,
Luben Tuikov <ltuikov@yahoo.com>,
SCSI Mailing List <linux-scsi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: I request inclusion of SAS Transport Layer and AIC-94xx into the kernel
Date: Fri, 30 Sep 2005 15:15:50 -0600 [thread overview]
Message-ID: <1128114950.10079.170.camel@bluto.andrew> (raw)
In-Reply-To: <433DA0DF.9080308@adaptec.com>
On Fri, 2005-09-30 at 16:32 -0400, Luben Tuikov wrote:
> On 09/30/05 16:14, Andrew Patterson wrote:
> >
> > Yes you can, which is what I am trying to do. However, is that library
> > also available on Solaris and Windows? Is it up to date? These are the
>
> Is the kernel the latest one? Is it up to date?
>
> See? Same argument.
>
> >>>Note that a sysfs implementation has problems. Binary attributes are
> >>>discouraged/not-allowed.
> >>
> >>I've never heard that. Is this similar to the argument
> >>"The sysfs tree would be too deep?"
> >
> >
> >>From Documentation/filesystes/sysfs.txt
> >
> > "Attributes should be ASCII text files, preferably with only one value
> > per file. It is noted that it may not be efficient to contain only
> > value per file, so it is socially acceptable to express an array of
> > values of the same type.
> >
> > Mixing types, expressing multiple lines of data, and doing fancy
> > formatting of data is heavily frowned upon. Doing these things may get
> > you publically humiliated and your code rewritten without notice."
>
> I see this talk _only_ about non-binary attributes.
I think that "ASCII text files" implies non-binary. As Willy has pointed
out, this has already been violated.
>
> Plus you have to admit: the SAS sysfs "smp_portal" binary
> attribute is very versatile: you completely control the
> expander from user space _if_ you can see it: It is
> almost like "point and click".
No problem with this.
>
> I imagine there would be GUIs built on top of it, which would
> actually implement that "point, click, control".
>
> > My understanding is that sysfs is meant to be human-readable. I do not
>
> But `cat /sysfs/.../smp_portal` _is_ human readable. See? Its size is
> 0 bytes and when you read it you get 0 data read.
I don't quite think your definition of human readable is the same as
mine. I think the intention is to do something like:
$ cat attribute
3 Gb/s
or
$ echo "3 Gb/s" >attribute
Rather than
$ cat attribute
gibberish.
or
$ echo "gibberish" >attribute
But again, this may be just a goal and not a hard and fast rule. I can
definitely see a use for binary attributes in sysfs. Configfs seems to
be designed for this sort of thing.
>
> > User space locking can only guarantee atomic operations in user space.
>
> And user space is the whole audience of this interface.
>
> > Not sure at the moment, can I guarantee this for the future?
>
> How far in the future? 1, 3, 6 months? 1, 3, 6 years?
> Plus if you need an attribute larger than 4K, you've got
> other problems to worry about.
>
> > There are as many as one would want. We now have 32 bit device numbers.
> > Old technology is fine as long as it works, especially if their is no
> > new technology to replace it. Note that I don't like the character
> > device solution either. What would really be nice is something that will
> > allow us to pass an arbitrary request buffer, and get an arbitrary
> > response buffer back in a single transaction,
> , locks it, then hangs.
> Here:
>
> /* User space lock */
>
> fd = open(smp_portal, ...);
> write(fd, smp_req, smp_req_size);
> read(fd, smp_resp, smp_resp_size);
> close(fd);
>
> /* User space unlock */
>
> > See above. This stuff works for trivial user-space apps. It will not
> > suffice for most storage management apps.
>
> Sorry but I completely fail to see this argument., locks it, then hangs.
>
> How will it "fail for most storage managament apps"?
Let's see, one example:
Process A opens an attribute and writes to it. Process B opens another
attribute and writes to it, affecting the result that process A will see
from its subsequent read. I suppose you could lock every attribute, but
that would be very error-prone, and not allow much concurrency.
Andrew
>
> Luben
>
next prev parent reply other threads:[~2005-09-30 21:16 UTC|newest]
Thread overview: 166+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-30 17:07 I request inclusion of SAS Transport Layer and AIC-94xx into the kernel Salyzyn, Mark
2005-09-30 17:53 ` Arjan van de Ven
2005-10-01 23:55 ` Alan Cox
2005-10-03 16:17 ` Luben Tuikov
2005-10-04 6:51 ` Andre Hedrick
2005-10-04 15:01 ` Luben Tuikov
2005-09-30 18:39 ` Andrew Patterson
2005-09-30 19:21 ` Luben Tuikov
2005-09-30 20:14 ` Andrew Patterson
2005-09-30 20:22 ` Matthew Wilcox
2005-09-30 21:44 ` Linus Torvalds
2005-10-01 17:46 ` Greg KH
2005-09-30 20:32 ` Luben Tuikov
2005-09-30 21:15 ` Andrew Patterson [this message]
2005-09-30 21:40 ` Joel Becker
2005-09-30 22:01 ` Luben Tuikov
2005-09-30 23:42 ` Marcin Dalecki
2005-10-03 13:54 ` Luben Tuikov
2005-10-03 16:29 ` Marcin Dalecki
2005-10-03 16:35 ` Andrew Patterson
2005-10-03 16:39 ` Luben Tuikov
2005-10-03 19:16 ` Marcin Dalecki
2005-10-03 21:26 ` Tomasz Kłoczko
2005-10-03 22:04 ` Ryan Anderson
2005-10-03 22:56 ` Linus Torvalds
2005-10-03 23:22 ` Al Viro
2005-10-04 13:55 ` Tomasz Kłoczko
2005-10-04 15:09 ` Linus Torvalds
2005-10-04 14:38 ` Luben Tuikov
2005-10-04 14:54 ` Jeff Garzik
2005-10-04 15:19 ` Luben Tuikov
2005-10-04 15:26 ` Jeff Garzik
2005-10-04 15:40 ` Luben Tuikov
2005-10-04 15:46 ` Matthew Wilcox
2005-10-04 6:30 ` Andre Hedrick
2005-10-01 0:02 ` Jeff Garzik
2005-10-01 0:01 ` Jeff Garzik
-- strict thread matches above, loose matches on Subject: below --
2005-09-30 1:28 Martin Fouts
2005-09-29 15:45 Moore, Eric Dean
2005-09-28 22:17 Moore, Eric Dean
2005-09-29 12:46 ` Luben Tuikov
2005-09-28 15:15 Moore, Eric Dean
2005-09-28 16:59 ` Luben Tuikov
2005-09-28 0:28 Moore, Eric Dean
2005-09-28 1:34 ` Andre Hedrick
2005-09-28 11:42 ` Luben Tuikov
2005-09-27 13:07 Luben Tuikov
2005-09-27 13:19 ` Christoph Hellwig
2005-09-27 15:01 ` Luben Tuikov
2005-09-27 15:53 ` James Bottomley
2005-09-27 19:35 ` Luben Tuikov
2005-09-27 20:34 ` Jeff Garzik
2005-09-27 21:44 ` Luben Tuikov
2005-09-27 22:01 ` Jeff Garzik
2005-09-27 23:03 ` Luben Tuikov
2005-09-27 23:32 ` Andrew Patterson
2005-09-28 2:07 ` Jeff Garzik
2005-09-26 19:38 Luben Tuikov
2005-09-27 21:55 ` Jeff Garzik
2005-09-27 22:51 ` Luben Tuikov
2005-09-27 23:14 ` Andre Hedrick
2005-09-28 11:37 ` Luben Tuikov
2005-09-28 12:32 ` Matthew Wilcox
2005-09-28 14:50 ` Linus Torvalds
2005-09-30 1:56 ` Junio C Hamano
2005-09-28 16:27 ` Patrick Mansfield
2005-09-28 16:34 ` Luben Tuikov
2005-09-28 19:45 ` Andre Hedrick
2005-09-28 20:56 ` Luben Tuikov
2005-09-28 22:35 ` Willy Tarreau
2005-09-28 23:22 ` Jeff Garzik
2005-09-28 23:29 ` David S. Miller
2005-09-29 5:30 ` Andre Hedrick
2005-09-29 7:24 ` David S. Miller
2005-09-30 7:36 ` Andre Hedrick
2005-09-30 18:34 ` Luben Tuikov
2005-09-30 18:50 ` Kyle Moffett
2005-09-30 19:08 ` Luben Tuikov
2005-09-30 21:31 ` Kyle Moffett
2005-09-30 22:10 ` Greg Freemyer
2005-09-30 22:19 ` Luben Tuikov
2005-09-30 23:54 ` Jeff Garzik
2005-10-01 4:58 ` Willy Tarreau
2005-10-03 15:08 ` Luben Tuikov
2005-10-03 14:04 ` Luben Tuikov
2005-09-30 22:14 ` Luben Tuikov
2005-10-01 0:33 ` Jeff Garzik
2005-10-03 14:18 ` Luben Tuikov
2005-10-03 16:01 ` Jeff Garzik
2005-09-30 20:45 ` James Bottomley
2005-09-30 22:05 ` Luben Tuikov
2005-10-01 0:38 ` Jeff Garzik
2005-10-03 15:27 ` Luben Tuikov
2005-10-03 16:28 ` Jeff Garzik
2005-09-30 22:04 ` Andre Hedrick
2005-09-30 22:32 ` Luben Tuikov
2005-09-30 23:57 ` Jeff Garzik
2005-10-03 14:15 ` Luben Tuikov
2005-10-03 15:57 ` Jeff Garzik
2005-10-03 16:23 ` Luben Tuikov
2005-10-03 16:48 ` Jeff Garzik
2005-10-03 19:03 ` Luben Tuikov
2005-10-03 19:32 ` Mike Christie
2005-10-03 20:15 ` Jeff Garzik
2005-10-03 19:10 ` Mike Christie
2005-09-30 18:51 ` Luben Tuikov
2005-09-29 14:33 ` Luben Tuikov
2005-09-29 14:48 ` Jeff Garzik
2005-09-29 15:50 ` Luben Tuikov
2005-09-29 16:54 ` Jeff Garzik
2005-09-29 18:25 ` Luben Tuikov
2005-09-29 15:15 ` grundig
2005-09-29 15:17 ` Bernd Petrovitsch
2005-09-29 16:33 ` Luben Tuikov
2005-09-29 16:56 ` Jeff Garzik
2005-09-29 16:58 ` Luben Tuikov
2005-09-29 17:03 ` Jeff Garzik
2005-09-29 18:09 ` Gerrit Huizenga
2005-09-29 17:13 ` Bernd Petrovitsch
2005-09-29 18:39 ` Luben Tuikov
2005-09-29 22:43 ` Joel Becker
2005-09-29 17:52 ` John Stoffel
2005-09-29 19:20 ` Bruce Ferrell
2005-09-28 22:43 ` Andre Hedrick
2005-09-29 15:04 ` Luben Tuikov
2005-09-29 15:08 ` Jeff Garzik
2005-09-29 16:22 ` Luben Tuikov
2005-09-29 19:09 ` Stefan Richter
2005-09-29 22:06 ` Luben Tuikov
2005-09-28 16:30 ` Valdis.Kletnieks
2005-09-28 16:35 ` Luben Tuikov
2005-09-28 2:02 ` Jeff Garzik
2005-09-28 20:36 ` Luben Tuikov
2005-09-28 21:00 ` Jeff Garzik
2005-09-28 22:10 ` Luben Tuikov
2005-09-28 23:04 ` Jeff Garzik
2005-09-29 4:04 ` Willy Tarreau
2005-09-29 7:44 ` Arjan van de Ven
2005-09-29 15:09 ` Luben Tuikov
2005-09-29 15:20 ` Jeff Garzik
2005-09-29 16:56 ` Luben Tuikov
2005-09-29 17:11 ` Jeff Garzik
2005-09-30 18:16 ` Joe Bob Spamtest
2005-09-29 17:15 ` Stefan Richter
2005-09-29 17:29 ` Jeff Garzik
2005-09-29 19:32 ` Willy Tarreau
2005-09-29 19:57 ` Linus Torvalds
2005-09-29 22:49 ` jerome lacoste
2005-09-29 23:20 ` Luben Tuikov
2005-09-29 23:57 ` Prasenjit Sarkar
2005-09-30 6:35 ` Andre Hedrick
2005-09-30 0:35 ` Linus Torvalds
2005-09-30 1:25 ` Hua Zhong
2005-09-30 2:42 ` Marcin Dalecki
2005-09-30 19:12 ` Joe Bob Spamtest
2005-09-30 19:38 ` Bob Copeland
2005-09-30 7:29 ` Douglas Gilbert
2005-09-30 14:23 ` Luben Tuikov
2005-09-30 16:26 ` Andrew Patterson
2005-09-30 16:47 ` Luben Tuikov
2005-09-30 14:07 ` Luben Tuikov
2005-09-30 5:31 ` Theodore Ts'o
2005-09-30 6:52 ` Andre Hedrick
2005-09-29 19:59 ` Stefan Richter
2005-09-29 19:37 ` Stefan Richter
2005-09-29 19:22 ` Stefan Richter
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